In general, semiconductor packages are used to protect a semiconductor die in a package body and to provide connection points for connecting the packaged die to external devices and circuitry. Ball grid array (BGA) packages are currently used to handle the high density and high pin-count of semiconductor die. In a typical BGA package, the semiconductor die is mounted to the top surface of a printed circuit board (PCB) type substrate. The die is wire bonded to electrical traces on the top surface of the substrate. The bond wires and die are then typically encapsulated for protection. Solder balls are bonded to the electrical traces on the bottom surface of the substrate to provide electrical connection to an underlying device, such as a PCB.
During operation of the integrated circuit, heat is generated by the die which must be removed from the package. Many packages use heat dissipation elements, such as heat slugs, heat spreaders, and heat sinks, attached or coupled to the die. These elements can be made of materials, such as aluminum, copper, steel, and alloys, which spread and remove the heat from the device.
With a cavity-down configuration, in which the die face is facing down towards the ball grid array, the die and bond wires are encapsulated in the cavity, and a heat dissipation element is typically attached to the back side of the die to form the top of the chip package. These types of configurations have high package or substrate profiles as well as high assembly costs. With a cavity-up configuration, in which the die face is facing up and away from the ball grid array, a chip lid is secured over the die and bond wires to dissipate heat generated by the circuit. However, these “drop-in” lids result in a high thermal resistance between the die and the heat spreader.
Accordingly, a ball grid array package with a heat dissipating element is desired without the disadvantages discussed above with conventional packages.